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Error: use of deleted function ... [message #49205]

Sun, 07 January 2018 15:48

idkfa46
Messages: 155
Registered: December 2011

Experienced Member

Dears,
I'm here back to you after long time without coding and without UPP Sad

because I have to modify my little software

I just made the following steps:
-I re-installed UPP (latest Nightly builds from website);
-I set up my old assembly;
-I tryed to compile it (both debug/release mode);

but i receive the following errors:
C:\Users\Matteo\Dropbox\2_Sviluppo++\Workspace_upp\LibVerifi che\Layout.h (147): error: use of deleted function 'Relazione::RelazioneFormat& Relazione::RelazioneFormat::operator=(const Relazione::RelazioneFormat&)'
C:\Users\Matteo\Dropbox\2_Sviluppo++\Workspace_upp\LibVerifi che\Materiali.cpp (1): In file included from C:\Users\Matteo\Dropbox\2_Sviluppo++\Workspace_upp\LibVerifi che\Materiali.cpp:1:0:
C:\Users\Matteo\Dropbox\2_Sviluppo++\Workspace_upp\LibVerifi che\Layout.h (136): note: 'Relazione::RelazioneFormat& Relazione::RelazioneFormat::operator=(const Relazione::RelazioneFormat&)' is implicitly
deleted because the default definition would be ill-formed:
...

Can you help me to undestand what is happinging please?

here is the code about class Relazioni()

class Relazione {
public:
	class RelazioneFormat : public Moveable<RelazioneFormat> {
		public:
			String Titolo;
			String IconaTitolo;
			Vector<String> Corpo;
			RelazioneFormat();
	};
private:
	RelazioneFormat format;

public:
	Relazione &Clear() 			{ RelazioneFormat f; format = f; return *this;}
	Relazione &Titolo(String s = "")	{ format.Titolo = s; return *this; }
	Relazione &Icona(String s = "")		{ format.IconaTitolo = s; return *this; }
	Relazione &AddCorpo(String s = "")	{ format.Corpo.Add(s); return *this; }
	Relazione &NewLine()			{ format.Corpo.Add("&"); return *this; }

	String GeneraRelazione();

	typedef Relazione CLASSNAME;
	Relazione(){};
};

thank you and happy new year!

Regards,
Matteo

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Re: Error: use of deleted function ... [message #49206 is a reply to message #49205]

Sun, 07 January 2018 16:40

Klugier
Messages: 1099
Registered: September 2012
Location: Poland, Kraków

Senior Contributor

Hello,

It seems that the compiler cannot generate operator= for some reasons. The following solution should fix your compilation problem:

Relazione &Clear() 			{ f = {}; return *this;}

// or
Relazione &Clear() 			{ f = RelazioneFormat(); return *this;}

If I will know more about this issue I will let you know. It would be good if you will migrate your code base to English Smile

However, I understand a lot from your current code.

Sincerely,
Klugier

U++ - one framework to rule them all.

[Updated on: Sun, 07 January 2018 16:41]

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Re: Error: use of deleted function ... [message #49207 is a reply to message #49206]

Sun, 07 January 2018 17:45

idkfa46
Messages: 155
Registered: December 2011

Experienced Member

Hi Klugier and thanks for your reply.

Your solution can't work because 'f' was not declared in the scope.

I tryed the following option too but without success:

Relazione &Clear() 	{ RelazioneFormat f; format = f.RelazioneFormat(); return *this;}

The problem should be about 'format = f' but I really can not understand why... Sad

Regards,
Matteo

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Re: Error: use of deleted function ... [message #49208 is a reply to message #49205]

Sun, 07 January 2018 17:51

Oblivion
Messages: 1202
Registered: August 2007

Senior Contributor

Hello Matteo, and welcome!

Klugier has already proposed a solution, yet another solution and explanation is as follows:

The reason seems to be that the RelazioneFormat class (in C++11 and above) has a implicitly defined move constructor;

Solution is easy, use pick():

Relazione &Clear()			{ RelazioneFormat f; format = pick(f); return *this;}
                                                                      -------
                                                                         ^

It is all explained here:

http://en.cppreference.com/w/cpp/language/move_constructor

Best regards,
Oblivion

Github page: https://github.com/ismail-yilmaz
upp-components: https://github.com/ismail-yilmaz/upp-components
Bobcat the terminal emulator: https://github.com/ismail-yilmaz/Bobcat

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Re: Error: use of deleted function ... [message #49209 is a reply to message #49208]

Sun, 07 January 2018 20:42

Klugier
Messages: 1099
Registered: September 2012
Location: Poland, Kraków

Senior Contributor

Hello,

Of course it should be:

Relazione &Clear() 			{ format = {}; return *this;}

Please read what "{}" means in c++11 if you are not familiar with this notation.

Declaring variable and picking it seems like over engineering here. We want simply reset variable to it's default state.

Sincerely,
Klugier

U++ - one framework to rule them all.

[Updated on: Sun, 07 January 2018 20:44]

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Re: Error: use of deleted function ... [message #49210 is a reply to message #49208]

Sun, 07 January 2018 20:50

idkfa46
Messages: 155
Registered: December 2011

Experienced Member

Thank you guys,
pick() function seams to be the right solution for me and the message error disappeared... btw, I have to read your link again because I didn't get the point at all yet!

If I understood well the problem is that now my build method is MINGW; if I go back to MSC9, the ones I used to build up the software, I should avoid this kind of error. Is it right?

In your opinion is better to update my code to the new methods? ...This error seems to be first of many many others! Smile

thanks,
Matteo

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Re: Error: use of deleted function ... [message #49242 is a reply to message #49205]

Wed, 10 January 2018 11:31

idkfa46
Messages: 155
Registered: December 2011

Experienced Member

Thank you guys,
I understood it a bit more now and

Relazione &Clear() 		{ format = {}; return *this;}

should be the best solution for my case!

Regards,
Matteo

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